MiR-26a and miR-26b mediate osteoarthritis progression by targeting FUT4 via NF-κB signaling pathway

Let-7a-5p derived from parathyroid hormone (1-34)-preconditioned BMSCs exosomes delays the progression of osteoarthritis by promoting chondrocyte proliferation and migration

BACKGROUND

Osteoarthritis (OA) is a prevalent degenerative joint disorder affecting over 240 million people worldwide, yet no disease-modifying therapies currently exist, with clinical management limited to symptomatic relief or joint replacement. Exosomes (Exos) from bone marrow mesenchymal stem cells (ExoBMSC) play positive role in the treatment of cartilage damage. Parathyroid hormone (PTH) (1-34) can enhance cartilage repair. Here, We found Exos from ExoBMSC reduces cartilage damage during treatment. Meanwhile, the Exos of PTH(1-34)-preconditioned BMSCs (ExoPTH) can alleviate OA better than ExoBMSC. Through MicroRNA (miRNA) sequencing analysis, this study aims to reveal the effects and potential mechanism of miRNA (let-7a-5p) in ExoPTH to repair OA cartilage.

METHODS

Differential centrifugation was used for isolating ExoBMSC and ExoPTH. Extract bone marrow mesenchymal stem cells from rats and utilize the C28/I2 chondrocytes line, the OA model was established using lipopolysaccharide (LPS; 1 µg/mL) in vitro. OA was induced in rats with intra-articular injection with collagenase-2. By performing a miRNA array, RNA-seq, in addition to bioinformatic analysis, the miRNA and the potential regulatory mechanism were detected. We compared in vitro let-7a-5p effects on the ability of OA chondrocytes to proliferate, migrate, apoptosis, and form the extracellular matrix (ECM). Histological and immunohistochemical assessments were used for evaluating cartilage pathology in vivo.

RESULTS

We extracted ExoBMSC and ExoPTH and established the OA model in vitro. Compared with ExoBMSC group, ExoPTH group has a stronger effect on promoting the proliferation and migration of chondrocytes. ExoBMSC and ExoPTH can inhibit the apoptosis of chondrocytes, but there was no significant difference between the two groups. The two most significant differences in groups ExoBMSC and ExoPTH are let-7a-5p. Let-7a-5p promotes OA chondrocytes proliferation and migration by inhibiting the expression of IL-6 in vitro experiments. For in vivo experiments, let-7a-5p delays the progression of OA.

CONCLUSION

Our study shows that ExoPTH may improve the regulatory inflammatory responses to delays the progression of OA by shuttling let-7a-5p. Let-7a-5p promoted chondrocytes migration and proliferation to suppress OA pathology by inhibiting IL-6/STAT3 pathway.

The Inhibitory Effect of the Active Ingredients in the Bushen Huoxue Formula on the IL-17A Signaling Pathway and Its Alleviating Effect on Osteoarthritis

Objective

Osteoarthritis (OA) stands as a prevalent degenerative disease worldwide. Despite the demonstrated therapeutic efficacy of the Bushen Huoxue formula (BSHXF) in treating OA, its underlying mechanism remains elusive. Network pharmacology is commonly employed for investigating drug-disease associations and processes. In this study, we employed network pharmacology alongside in vitro and in vivo experiments to elucidate the molecular mechanism by which BSHXF treats OA.

Methods

Based on the TCMSP database, active components of BSHXF were screened, and OA-related targets were retrieved from GeneCard and DisGeNET to construct a "component-target-pathway" network using Cytoscape. Core target functions and pathways (KEGG/GO) were analyzed through STRING and Metascape, while component-target binding affinity was validated via Autodock. For in vitro experiments, an IL-1β-induced chondrocyte inflammation model was established, and key protein expression was detected by Western blot and immunofluorescence. For in vivo experiments, an OA model was created by medial meniscectomy of the knee joint in rats, and therapeutic efficacy was assessed using histological staining and micro-CT.

Results

This study screened 89 active ingredients of BSHXF and identified 189 common targets. Network pharmacological analysis revealed luteolin and tanshinone IIA as the most crucial active ingredients in treating OA with BSHXF. The potential mechanisms of action for BSHXF in OA treatment involve inflammation inhibition, immune function regulation, and resistance to oxidative stress, with a significant regulatory role played by the IL-17 signaling pathway. Molecular docking results demonstrated luteolin's strong binding affinity to key targets such as B-cell lymphoma 2 (Bcl-2), Matrix metalloproteinase-9 (Mmp-9), and IL-6.In vitro experiments demonstrated that BSHXF significantly suppressed IL-1β-induced inflammatory responses in chondrocytes, downregulating IL-17A expression (p < 0.05), reducing the expression of MMP-9 (p < 0.05) and IL-6 (p < 0.05), and inhibiting apoptosis. Additionally, in vivo experiments revealed that the high-dose BSHXF group (150 mg/kg) markedly alleviated cartilage damage in OA rats, with OARSI scores significantly decreased compared to the model group (p < 0.05). Micro-CT analysis showed that BSHXF inhibited osteophyte formation and ameliorated OA pathological conditions.

Conclusion

BSHXF has the potential to alleviate OA by suppressing inflammation, inhibiting cartilage apoptosis and hindering extracellular matrix degradation via the IL-17 signaling pathway. Our study elucidated the molecular mechanisms underlying the therapeutic effects of BSHXF on OA, thus highlighting its further research implications as a novel drug candidate.

Extracellular Vesicle-Derived microRNA Crosstalk Between Equine Chondrocytes and Synoviocytes-An In Vitro Approach

This study describes a novel technique to analyze the extracellular vesicle (EV)-derived microRNA (miRNA) crosstalk between equine chondrocytes and synoviocytes. Donor cells (chondrocytes, n = 8; synoviocytes, n = 9) were labelled with 5-ethynyl uridine (5-EU); EVs were isolated from culture media and incubated with recipient cells (chondrocytes [n = 5] were incubated with synoviocyte-derived EVs, and synoviocytes [n = 4] were incubated with chondrocyte-derived EVs). Total RNA was extracted from recipient cells; the 5-EU-labelled RNA was recovered and sequenced. Differential expression analysis, pathway analysis, and miRNA target prediction were performed. Overall, 198 and 213 miRNAs were identified in recipient synoviocytes and chondrocytes, respectively. The top five most abundant miRNAs were similar for synoviocytes and chondrocytes (eca-miR-21, eca-miR-221, eca-miR-222, eca-miR-100, eca-miR-26a), and appeared to be linked to joint homeostasis. There were nine differentially expressed (p < 0.05) miRNAs (eca-miR-27b, eca-miR-23b, eca-miR-31, eca-miR-191a, eca-miR-199a-5p, eca-miR-143, eca-miR-21, eca-miR-181a, and eca-miR-181b) between chondrocytes and synoviocytes, which appeared to be linked to migration of cells, apoptosis, cell viability of connective tissue cell, and inflammation. In conclusion, the reported technique was effective in recovering and characterizing the EV-derived miRNA crosstalk between equine chondrocytes and synoviocytes and allowed for the identification of EV-communicated miRNA patterns potentially related to cell viability, inflammation, and joint homeostasis.

Fucosyltransferase 4 upregulates P-gp expression for chemoresistance via NF-κB signaling pathway

BACKGROUND

Multidrug resistance (MDR) poses a significant obstacle to developing chemotherapeutic treatments. In previous studies using a traditional model of adriamycin resistance (ADR) with K562 cells, we demonstrated that N-acetylglucosaminyltransferase III (GnT-III) expression negatively regulates chemoresistance. Additionally, we observed that fucosylation levels were increased in the ADR cells.

METHOD

Fucosylation levels were determined using lectin blot, western blot, and flow cytometry. Gene expression levels were analyzed via qPCR. We generated a FUT4 knockout (KO) ADR cell line using CRISPR/Cas9 technology. Cytotoxicity and drug efflux assays were conducted to evaluate chemotherapy tolerance.

RESULTS

The expression levels of FUT4 and its products, the LeX antigens, were significantly upregulated in the ADR cells compared to the parental K562 cells. The FUT4 KO reduced the elevated levels of P-glycoprotein (P-gp) found in ADR cells and exhibited increased sensitivity to chemotherapeutic drugs. Furthermore, restoring FUT4 expression in the KO cells effectively reversed P-gp expression, drug efflux, and chemoresistance. Given the critical role of the NF-κB pathway in P-gp expression, we investigated NF-κB signaling and found that the phosphorylation levels of p65 were significantly increased in the ADR cells but were downregulated in the FUT4 KO cells. Furthermore, the restoration of FUT4 rescued the phosphorylation levels of p65.

CONCLUSIONS

FUT4 specifically upregulates P-gp expression related to chemoresistance through the NF-κB signaling pathway.

GENERAL SIGNIFICANCE

This study highlights the importance of FUT4 in chemoresistance and suggests it may serve as a promising target for combating MDR.

Silencing FUT4 Inhibits the Progression of Osteosarcoma through Activation of FOXO1

BACKGROUND

It has been reported that inhibition of Fucosyltransferase4 (FUT4) to activate Forkhead box O1 (FOXO1) can lead to apoptosis of cancer cells, however, the mechanism in osteosarcoma is still unclear.

OBJECTIVE

To explore the biological significance of the connection between FUT4 and FOXO1 in osteosarcoma growth.

METHODS

In vitro tests were conducted using the human osteoblast cell line and the osteosarcoma cell lines. QRT-PCR assay as well as western blot assay were used to ascertain the relative expression levels of FUT4 and FOXO1 in the cells. By using the CCK-8 assay, colony assay, EDU assay, wound healing assay and Transwell assay, osteosarcoma cells' ability to proliferate, migrate and invade were examined in relation to si- FUT4. TUNEL test was used to evaluate Si-impact FUT4's on KHOS and U2OS apoptosis in osteosarcoma cells. Western blot assay was used to identify the expression of proliferative, migrating and apoptosis-related protein markers in osteosarcoma cells KHOS and U2OS and the expression of important proteins in the Wnt/ β-catenin signaling pathway.

RESULTS

In comparison with osteoblasts, osteosarcoma cells expressed more FUT4. The osteosarcoma cells' capacities to proliferate, invade, and migrate were markedly inhibited by the inhibition of FUT4 expression, which also increased osteosarcoma cell apoptosis. The Wnt/β-catenin signaling pathway was blocked by upregulating FOXO1 expression, which was in turn inhibited by inhibiting FUT4 expression.

CONCLUSION

Osteosarcoma cells express more FUT4. The Wnt/β-catenin signaling pathway has a significant effect on osteosarcoma cell death, and inhibition of FUT4 expression may target FOXO1 activation to decrease osteosarcoma cells' ability to proliferate, invade, and migrate.

FUT3 facilitates glucose metabolism of lung adenocarcinoma via activation of NF-κB pathway

OBJECTIVE

Fucosyltransferases (FUTs) molecules have been identified to be involved in carcinogenesis of malignant tumors. Nevertheless, the biological function of fucosyltransferases-3 (FUT3) in lung adenocarcinoma (LUAD) malignant phenotype remains unclear. Herein, we investigated the association between FUT3 and LUAD pathological process.

METHODS

Immunochemistry, RT-qPCR and western blot assays were conducted to evaluate the expression of FUT3 in LUAD and corresponding adjacent tissues. The prognostic value of FUT3 was assessed via Kaplan‑Meier plotter database. The biological process and potential mechanism of FUT3 in LUAD were conducted via GSEA. Additionally, immunofluorescence and metabolite activity detection were performed to determine the potential role of FUT3 in LUAD glucose metabolism. The active biomarkers associated with NF-κB signaling pathway were detected via western blot. Subcutaneous tumor model was conducted to analyze the effect of FUT3 on tumorigenesis of LUAD.

RESULTS

FUT3 was remarkably upregulated in LUAD tissues compared with adjacent tissues from individuals. FUT3 overexpression may predict poor prognosis of LUAD patients. Knockdown of FUT3 significantly inhibited tumor proliferation, migration and glucometabolic alteration in LUAD cells. Moreover, GSEA demonstrated that elevated FUT3 was positively related to NF-κB signaling pathway. Additionally, in vitro and in vivo assays also indicated that downregulation of FUT3 resulted in the suppression of oncogenesis and glucose metabolism via inactivation of NF-κB pathway.

CONCLUSION

Our findings demonstrated that FUT3 was involved in glucometabolic process and tumorigenesis of LUAD via NF-κB signaling pathway. FUT3 may be an optimal target for diagnosis and treatment of LUAD patients.

MicroRNA-15a/β1,4-GalT-I axis contributes to cartilage degeneration via NF-κB signaling in osteoarthritis

OBJECTIVE

Osteoarthritis is a condition characterized by articular cartilage degradation. The increased expression of β1,4-Galactosyltransferase-I (β1,4-GalT-I) in the articular cartilage of osteoarthritis patients was related to an inflammatory response. The aim of this study was to elucidate the role of β1,4-GalT-I in osteoarthritis. This study aimed to determine the function of 1,4-GalT-I in osteoarthritis.

METHODS

The osteoarthritis mouse model with the destabilization of the medial meniscus was established by microsurgical technique. Pathological changes in articular cartilage were observed by hematoxylin and eosin staining and safranin O-fast green staining. Quantitative real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assays were used to observe mRNA and protein expression, respectively. RNA interactions were verified by a luciferase reporter assay. SA-β-Gal staining was used to assess chondrocyte senescence. Immunofluorescence staining was conducted to observe the localization of Nuclear Factor-kappaB (NF-κB).

RESULTS

β1,4-GalT-I and microRNA-15a (miR-15a) show high and low expression in the articular cartilage of osteoarthritis, respectively. MiR-15a inhibits the mRNA translation of β1,4-GalT-I. β1,4-GalT-I promotes extracellular matrix degradation, senescence, and NF-κB activation in IL-1β-stimulated chondrocytes, which can be reversed by overexpression of miR-15a. Intra-articular injection of microRNA-15a ameliorates cartilage degeneration by inhibiting β1,4-GalT-I and phosphorylation of NF-κB in vivo.

CONCLUSION

The authors clarified that the miR-15a/β1,4-GalT-I axis inhibits the phosphorylation of NF-κB thereby inhibiting extracellular matrix degradation and senescence in chondrocytes to alleviate cartilage degeneration in osteoarthritis. MiR-15a and β1,4-GalT-I may serve as potentially effective targets for the future treatment of osteoarthritis.

miR-26a deficiency is associated with bone loss and reduced muscle strength but does not affect severity of cartilage damage in osteoarthritis

Osteoarthritis (OA) is the most common age-related joint disease. However, the role of many microRNAs (miRNA) in skeletal development and OA pathogenesis has not been sufficiently elucidated using genetically modified mice with gain- and loss-of-function models. We generated Cartilage-specific miR-26a overexpressing (Col2a1-Cre;miR-26a Tg^fl/fl: Cart-miR-26a Tg) mice and global miR-26a knockout (miR-26a KO) mice. The purpose of the present study was to determine the role of miR-26a in OA pathogenesis using aging and surgically induced models. Skeletal development of Cart-miR-26a Tg and miR-26a KO mice was grossly normal. Knee joints were evaluated by histological grading systems. In surgically-induced OA and aging models (12 and 18 months of age), Cart-miR-26a Tg mice and miR-26a KO mice exhibited OA-like changes such as proteoglycan loss and cartilage fibrillation with no significant differences in OARSI score (damage of articular cartilage) compared with control mice. However, miR-26a KO mice reduced muscle strength and bone mineral density at 12 months of age. These findings indicated that miR-26a modulates bone loss and muscle strength but has no essential role in aging-related or post-traumatic OA.

The Mutual Relationship between Glycosylation and Non-Coding RNAs in Cancer and Other Physio-Pathological Conditions

Glycosylation, which consists of the enzymatic addition of sugars to proteins and lipids, is one of the most important post-co-synthetic modifications of these molecules, profoundly affecting their activity. Although the presence of carbohydrate chains is crucial for fine-tuning the interactions between cells and molecules, glycosylation is an intrinsically stochastic process regulated by the relative abundance of biosynthetic (glycosyltransferases) and catabolic (glycosidases) enzymes, as well as sugar carriers and other molecules. Non-coding RNAs, which include microRNAs, long non-coding RNAs and circRNAs, establish a complex network of reciprocally interacting molecules whose final goal is the regulation of mRNA expression. Likewise, these interactions are stochastically regulated by ncRNA abundance. Thus, while protein sequence is deterministically dictated by the DNA/RNA/protein axis, protein abundance and activity are regulated by two stochastic processes acting, respectively, before and after the biosynthesis of the protein axis. Consequently, the worlds of glycosylation and ncRNA are closely interconnected and mutually interacting. In this paper, we will extensively review the many faces of the ncRNA-glycosylation interplay in cancer and other physio-pathological conditions.

Osteoarthritis and microRNAs: Do They Provide Novel Insights into the Pathophysiology of This Degenerative Disorder?

Osteoarthritis (OA) is one of the most prevalent degenerative joint diseases in older adults and a leading cause of disability. Recent research studies have evidenced the importance of mi-croRNAs (miRs) in the pathogenesis of OA. In the present review, we focused on current literature findings on dysregulated miRs involved in the pathophysiology of OA. From the 35 case-control studies including OA patients compared to healthy controls, a total of 54 human miRs were identified to be dysregulated in OA. In total, 41 miRs were involved in the pathophysiological processes of OA, including apoptosis, inflammation, and proliferation, having either a protective or a progressive role in OA. The discovery of altered miR levels in OA patients compared to healthy controls determines a better understanding of the molecular mechanisms involved in the pathophysiology of OA and could open novel horizons in the field of orthopedics.

Characterization of microRNA Levels in Synovial Fluid from Knee Osteoarthritis and Anterior Cruciate Ligament Tears

This study investigated modifications of microRNA expression profiles in knee synovial fluid of patients with osteoarthritis (OA) and rupture of the anterior cruciate ligament (ACL). Twelve microRNAs (26a-5p, 27a-3p, let7a-5p, 140-5p, 146-5p, 155-5p, 16-5p,186-5p, 199a-3p, 210-3p, 205-5p, and 30b-5p) were measured by real-time quantitative polymerase chain reaction (RT-qPCR) in synovial fluids obtained from 30 patients with ACL tear and 18 patients with knee OA. These 12 miRNAs were chosen on the basis of their involvement in pathological processes of bone and cartilage. Our results show that miR-26a-5p, miR-186-5p, and miR-30b-5p were expressed in the majority of OA and ACL tear samples, whereas miR-199a-3p, miR-210-3p, and miR-205-5p were detectable only in a few samples. Interestingly, miR-140-5p was expressed in only one sample of thirty in the ACL tear group. miR-140-5p has been proposed to modulate two genes (BGN and COL5A1100) that are involved in ligamentous homeostasis; their altered expression could be linked with ACL rupture susceptibility. The expression of miR-30b-5p was higher in OA and chronic ACL groups compared to acute ACL samples. We provide evidence that specific miRNAs could be detected not only in synovial fluid of patients with OA, but also in post-traumatic ACL tears.

The Role of Mitochondrial Metabolism, AMPK-SIRT Mediated Pathway, LncRNA and MicroRNA in Osteoarthritis

Osteoarthritis (OA) is the most common joint disease characterized by degeneration of articular cartilage and causes severe joint pain, physical disability, and impaired quality of life. Recently, it was found that mitochondria not only act as a powerhouse of cells that provide energy for cellular metabolism, but are also involved in crucial pathways responsible for maintaining chondrocyte physiology. Therefore, a growing amount of evidence emphasizes that impairment of mitochondrial function is associated with OA pathogenesis; however, the exact mechanism is not well known. Moreover, the AMP-activated protein kinase (AMPK)–Sirtuin (SIRT) signaling pathway, long non-coding RNA (lncRNA), and microRNA (miRNA) are important for regulating the physiological and pathological processes of chondrocytes, indicating that these may be targets for OA treatment. In this review, we first focus on the importance of mitochondria metabolic dysregulation related to OA. Then, we show recent evidence on the AMPK-SIRT mediated pathway associated with OA pathogenesis and potential treatment options. Finally, we discuss current research into the effects of lncRNA and miRNA on OA progression or inhibition.

An NF-κB- and Therapy-Related Regulatory Network in Glioma: A Potential Mechanism of Action for Natural Antiglioma Agents

High-grade gliomas are among the most aggressive malignancies, with significantly low median survival. Recent experimental research in the field has highlighted the importance of natural substances as possible antiglioma agents, also known for their antioxidant and anti-inflammatory action. We have previously shown that natural substances target several surface cluster of differentiation (CD) markers in glioma cells, as part of their mechanism of action. We analyzed the genome-wide NF-κB binding sites residing in consensus regulatory elements, based on ENCODE data. We found that NF-κB binding sites reside adjacent to the promoter regions of genes encoding CD markers targeted by antiglioma agents (namely, CD15/FUT4, CD28, CD44, CD58, CD61/SELL, CD71/TFRC, and CD122/IL2RB). Network and pathway analysis revealed that the markers are associated with a core network of genes that, altogether, participate in processes that associate tumorigenesis with inflammation and immune evasion. Our results reveal a core regulatory network that can be targeted in glioblastoma, with apparent implications in individuals that suffer from this devastating malignancy.

Ten Hotspot MicroRNAs and Their Potential Targets of Chondrocytes Were Revealed in Osteoarthritis Based on Bibliometric Analysis

Background

Osteoarthritis (OA) is one of the most common joint disorders and debilitating diseases. Current evidence suggests that microRNAs (miRNAs) play a critical role in the pathogenesis of OA and have great potential as new biomarkers and therapeutic targets. We aimed to analyze the trends and research status on miRNAs in OA and further demonstrate the hotspot miRNAs in OA via CiteSpace and VOSviewer.

Methods

Publications regarding miRNAs and OA were extracted from the Web of Science (WOS) database on October 30, 2021. We assessed the number of publications, institutions, countries, authors, journals, cited references, and keywords with the help of the software tools CiteSpace and VOSviewer.

Results

A total of 1109 articles were included. Research related to miRNAs and OA began to appear in 2008, and the overall trend is increasing. Chinese institutions have a leading advantage in the number of publications but lack high-quality and high-cited research and are laggard in co-cited literature. Ten miRNAs including miR-140, miR-146, miR-34, miR-181, miR-27, miR-9, miR-29, miR-21, miR-26, and miR-155 and chondrocytes were revealed as the most obvious miRNAs and a potential target for OA based on bibliometric analysis. More focus will be placed on a comprehensive study on chondrocytes regulated by miRNAs, which may accelerate possible diagnostic biomarkers and diagnostic biomarkers of OA in the future.

Crosstalk Among circRNA/lncRNA, miRNA, and mRNA in Osteoarthritis

Osteoarthritis (OA) is a joint disease that is pervasive in life, and the incidence and mortality of OA are increasing, causing many adverse effects on people's life. Therefore, it is very vital to identify new biomarkers and therapeutic targets in the clinical diagnosis and treatment of OA. ncRNA is a nonprotein-coding RNA that does not translate into proteins but participates in protein translation. At the RNA level, it can perform biological functions. Many studies have found that miRNA, lncRNA, and circRNA are closely related to the course of OA and play important regulatory roles in transcription, post-transcription, and post-translation, which can be used as biological targets for the prevention, diagnosis, and treatment of OA. In this review, we summarized and described the various roles of different types of miRNA, lncRNA, and circRNA in OA, the roles of different lncRNA/circRNA-miRNA-mRNA axis in OA, and the possible prospects of these ncRNAs in clinical application.

Downregulation of LncRNA OIP5-AS1 Induced by IL-1β Aggravates Osteoarthritis via Regulating miR-29b-3p/PGRN

BACKGROUND

Long noncoding RNA (lncRNA) OIP5 antisense RNA 1 (OIP5-AS1) is an oncogenic lncRNA; however, its role in osteoarthritis (OA) pathology still remains unknown.

MATERIALS AND METHODS

qRT-PCR was performed to measure the expressions of OIP5-AS1, miR-29b-3p and progranulin (PGRN) mRNA in OA cartilage tissues and normal cartilage tissues. Chondrocyte cell lines, CHON-001 and ATDC5, were treated with different doses of interleukin-1β (IL-1β) to induce the inflammatory response. Overexpression plasmids, microRNA mimics, microRNA inhibitors and small interfering RNAs were constructed and transfected into CHON-001 and ATDC5 cells. CCK-8 assay was used for determining the cell viability and Transwell assay was used for monitoring cell migration. Western blot was applied to measure the expressions of apoptosis-related proteins. Enzyme-linked immunosorbent assay (ELISA) was adopted to measure the contents of inflammatory factors. StarBase and TargetScan were used to predict the binding sites between OIP5-AS1 and miR-29b-3p, miR-29b-3p and 3'-UTR of PGRN respectively, which were verified by dual luciferase reporter assay.

RESULTS

OIP5-AS1 and PGRN mRNA were downregulated while miR-29b-3p was upregulated in OA tissues and models. The up-regulated OIP5-AS1 facilitated the proliferation and migration of CHON-001 and ATDC5 cells, while ameliorated the apoptosis and inflammatory response. However, miR-29b-3p had opposite effects. PGRN was identified as a target gene of miR-29b-3p, which could be indirectly suppressed by OIP5-AS1 knockdown.

CONCLUSION

Downregulation of OIP5-AS1 induced by IL-1β could inhibit the proliferation and migration abilities of CHON-001 and ATDC5 cells and facilitate the apoptosis and inflammation response via regulating miR-29b-3p/PGRN axis.

Disease-modifying therapeutic strategies in osteoarthritis: current status and future directions

Osteoarthritis (OA) is the most common form of arthritis. It is characterized by progressive destruction of articular cartilage and the development of chronic pain and constitutes a considerable socioeconomic burden. Currently, pharmacological treatments mostly aim to relieve the OA symptoms associated with inflammation and pain. However, with increasing understanding of OA pathology, several potential therapeutic targets have been identified, enabling the development of disease-modifying OA drugs (DMOADs). By targeting inflammatory cytokines, matrix-degrading enzymes, the Wnt pathway, and OA-associated pain, DMOADs successfully modulate the degenerative changes in osteoarthritic cartilage. Moreover, regenerative approaches aim to counterbalance the loss of cartilage matrix by stimulating chondrogenesis in endogenous stem cells and matrix anabolism in chondrocytes. Emerging strategies include the development of senolytic drugs or RNA therapeutics to eliminate the cellular or molecular sources of factors driving OA. This review describes the current developmental status of DMOADs and the corresponding results from preclinical and clinical trials and discusses the potential of emerging therapeutic approaches to treat OA.

MicroRNA-183 attenuates osteoarthritic pain by inhibiting the TGFα-mediated CCL2/CCR2 signalling axis

AIMS

MicroRNA-183 (miR-183) is known to play important roles in osteoarthritis (OA) pain. The aims of this study were to explore the specific functions of miR-183 in OA pain and to investigate the underlying mechanisms.

METHODS

Clinical samples were collected from patients with OA, and a mouse model of OA pain was constructed by surgically induced destabilization of the medial meniscus (DMM). Reverse transcription quantitative polymerase chain reaction was employed to measure the expression of miR-183, transforming growth factor α (TGFα), C-C motif chemokine ligand 2 (CCL2), proinflammatory cytokines (interleukin (IL)-6, IL-1β, and tumour necrosis factor-α (TNF-α)), and pain-related factors (transient receptor potential vanilloid subtype-1 (TRPV1), voltage-gated sodium 1.3, 1.7, and 1.8 (Nav1.3, Nav1.7, and Nav1.8)). Expression of miR-183 in the dorsal root ganglia (DRG) of mice was evaluated by in situ hybridization. TGFα, CCL2, and C-C chemokine receptor type 2 (CCR2) levels were examined by immunoblot analysis and interaction between miR-183 and TGFα, determined by luciferase reporter assay. The extent of pain in mice was measured using a behavioural assay, and OA severity assessed by Safranin O and Fast Green staining. Immunofluorescent staining was conducted to examine the infiltration of macrophages in mouse DRG.

RESULTS

miR-183 was downregulated in tissue samples from patients and mice with OA. In DMM mice, overexpression of miR-183 inhibited the expression of proinflammatory cytokines (IL-6, IL-1β, TNF-α) and pain-related factors (TRPV1, Nav1.3, Nav1.7, Nav1.8) in DRG. OA pain was relieved by miR-183-mediated inhibition of macrophage infiltration, and dual luciferase reporter assay demonstrated that miR-183 directly targeted TGFα.

CONCLUSION

Our data demonstrate that miR-183 can ameliorate OA pain by inhibiting the TGFα-CCL2/CCR2 signalling axis, providing an excellent therapeutic target for OA treatment. Cite this article: Bone Joint Res 2021;10(8):548-557.

Oligonucleotide Therapies in the Treatment of Arthritis: A Narrative Review

Osteoarthritis (OA) and rheumatoid arthritis (RA) are two of the most common chronic inflammatory joint diseases, for which there remains a great clinical need to develop safer and more efficacious pharmacological treatments. The pathology of both OA and RA involves multiple tissues within the joint, including the synovial joint lining and the bone, as well as the articular cartilage in OA. In this review, we discuss the potential for the development of oligonucleotide therapies for these disorders by examining the evidence that oligonucleotides can modulate the key cellular pathways that drive the pathology of the inflammatory diseased joint pathology, as well as evidence in preclinical in vivo models that oligonucleotides can modify disease progression.

Roles of long non‑coding RNA in osteoarthritis (Review)

Osteoarthritis (OA) is a chronic bone and joint disease characterized by articular cartilage degeneration and joint inflammation and is the most common form of arthritis. The clinical manifestations of OA are chronic pain and joint activity disorder, which severely affect the patient quality of life. Long non-coding RNA (lncRNA) is a class of RNA molecules >200 nucleotides long that are expressed in animals, plants, yeast, prokaryotes and viruses. lncRNA molecules lack an open reading frame and are not translated into protein. The present review collated the results of recent studies on the role of lncRNA in the pathogenesis of OA to provide information for the prevention, diagnosis and treatment of OA.

MicroRNA-26b-5p alleviates murine collagen-induced arthritis by modulating Th17 cell plasticity

Rheumatoid arthritis (RA) is a chronic autoimmune disease, and the abnormal differentiation of IL-17-producing T helper (Th17) cells is an important factor in the pathogenesis. Previous studies have shown that microRNAs (miRNAs, miR) act as key regulators of Th17 cells. However, the effects of miRNAs on Th17 cell differentiation and plasticity in RA are not clear. In this study, not only low miR-26b-5p expression and high IL-17A level were observed in the peripheral blood of RA patients, but also the negative correlation between miR-26b-5p and IL-17A was explored. The changes in collagen-induced arthritis (CIA) mice were consistent with those in RA patients. The results of in vitro experiments showed that miR-26b-5p mainly inhibited the initial differentiation of Th17 cells but did not impact the differentiation of induced-Treg into Th17-like cells. Meanwhile, miR-26b-5p mimics treatment alleviated inflammatory responses and reduced Th17 proportion in CIA mice. These results indicated that miR-26b-5p could alleviate the development of mice CIA by inhibiting the excessive Th17 cells, and that miR-26b-5p could modulate the plasticity of Th17 cell differentiation in RA, mainly block the initial differentiation. This may provide a novel strategy for the clinical treatment of RA.

MiR-26a inhibits the inflammatory response of microglia by targeting HMGA2 in intracerebral hemorrhage

Objective

Intracerebral hemorrhage (ICH) is a common cerebrovascular disease with high mortality and poor prognosis. Therefore, the biological function and underlying molecular mechanism of miR-26a in inflammatory injury following ICH was investigated.

Methods

The potential role of miR-26a was investigated in lipopolysaccharide (LPS)-treated microglial cells by quantitative real-time PCR. To explore the potential role of HMGA2 in the miR-26a-regulated inflammatory response, LPS-induced microglial cells were cotransfected with an miR-26a mimic and pcDNA-HMGA2. Then, lentivirus-mediated overexpression of an miR-26a mimic in mouse microglial cells was performed, and the effects of miR-26a treatment on IL-6, IL-1β, and TNF-α expression in the mouse brain, neurological behavior, and rotarod test performance of mice after ICH were observed.

Results

MiR-26a was significantly downregulated in LPS-treated microglia and ICH mouse models. MiR-26a markedly reduced IL-6, IL-1β, and TNF-α expression in LPS-treated microglial cells. Furthermore, HMGA2 was verified as a direct target of miR-26a. In vivo, miR-26a overexpression in mouse microglial cells significantly suppressed proinflammatory cytokine expression in mouse brains and markedly improved the neurological behavior and rotarod test performance of mice after ICH.

Conclusion

MiR-26a remarkably inhibited proinflammatory cytokine release by targeting HMGA2, indicating that miR-26a could protect against secondary brain injury following ICH.

Long noncoding RNA TUG1 regulates degradation of chondrocyte extracellular matrix via miR-320c/MMP-13 axis in osteoarthritis

Osteoarthritis (OA) is a common chronic joint disease. This study aimed to explore the function of long noncoding RNA taurine-upregulated gene 1 (TUG1) in the progression and initiation of OA. Levels of TUG1, microRNA-320c (miR-320c) and fucosyltransferase 4 (FUT4) were examined via quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and flow cytometry assays were used to detect cell viability and apoptosis, respectively. The expression of relative proteins was measured using Western blot. The interaction between miR-320c and TUG1 or FUT4 was confirmed utilizing dual-luciferase reporter and RNA immunoprecipitation assays. In this study, levels of TUG1 and FUT4 were distinctly upregulated, but miR-320c level significantly decreased in OA tissues and chondrocytes derived from OA tissues as well as in IL-1β-stimulated C28/I2 cells. Mechanically, TUG1 sponged miR-320c and miR-320c targeted FUT4. In addition, TUG1 knockdown accelerated cell proliferation and repressed apoptosis and extracellular matrix (ECM) degradation in IL-1β-induced C28/I2 cells, whereas these effects of TUG1 deletion were rescued by either miR-320c inhibitor or FUT4 upregulation. Meanwhile, TUG1 sponged miR-320c to regulate FUT4 expression in IL-1β-induced C28/I2 cells. Collectively, TUG1 modulated cell proliferation, apoptosis and ECM degradation in IL-1β-induced C28/I2 cells via the miR-320c/FUT4 axis, providing a new insight into the OA treatment.

Candidates for Intra-Articular Administration Therapeutics and Therapies of Osteoarthritis

Osteoarthritis (OA) of the knee is a disease that significantly decreases the quality of life due to joint deformation and pain caused by degeneration of articular cartilage. Since the degeneration of cartilage is irreversible, intervention from an early stage and control throughout life is important for OA treatment. For the treatment of early OA, the development of a disease-modifying osteoarthritis drug (DMOAD) for intra-articular (IA) injection, which is attracting attention as a point-of-care therapy, is desired. In recent years, the molecular mechanisms involved in OA progression have been clarified while new types of drug development methods based on gene sequences have been established. In addition to conventional chemical compounds and protein therapeutics, the development of DMOAD from the new modalities such as gene therapy and oligonucleotide therapeutics is accelerating. In this review, we have summarized the current status and challenges of DMOAD for IA injection, especially for protein therapeutics, gene therapy, and oligonucleotide therapeutics.

The interaction between miRNAs/lncRNAs and nuclear factor-κB (NF-κB) in human disorders

Nuclear factor-κB (NF-κB) represents a group of inducible transcription factors (TFs) regulating the expression of a great variety of genes implicated in diverse processes, particularly modulation of immune system responses. This TF has functional interactions with non-coding RNAs, constructing a complicated network through which NF-κB, miRNAs, and lncRNAs coordinately regulate gene expression at different facets. This type of interaction is involved in the pathophysiology of several human disorders including both neoplastic disorders and non-neoplastic conditions. MALAT1 and NKILA are among lncRNAs whose interactions with NF-κB have been vastly assessed in different conditions including cancer and inflammatory conditions. In addition, miR-146a/b has functional interactions with this TF in different contexts. Although miRNAs have mutual interactions with NF-κB, the regulatory role of miRNAs on this TF has been more clarified. The aim of the current review is to explore the function of NF-κB-related miRNAs and lncRNAs in these two types of human disorders.

MicroRNA-200b relieves LPS-induced inflammatory injury by targeting FUT4 in knee articular chondrocytes in vitro

Osteoarthritis (OA), characterized by the degeneration of articular cartilage, is a major problem in aging populations, and cartilage chondrocytes have been indicated to serve a curial role in the progression of OA. MicroRNA-200b-3p (miR-200b) was preliminarily identified to participate in OA. However, its role and mechanism of action in injured chondrocytes in OA remain unclear to date. In the present study, lipopolysaccharide (LPS)-treated cells isolated from normal knee articular cartilage were used to mimic inflammatory injury of OA chondrocytes. Cell viability, apoptosis and inflammatory responses were detected using Cell Counting Kit-8, flow cytometry and enzyme-linked immunosorbent assay, respectively. The expression levels of miR-200b and fucosyltransferase-4 (FUT4) were measured by reverse transcription-quantitative PCR and western blotting. The association between miR-200b and FUT4 was verified using TargetScan software, dual-luciferase reporter assay and RNA immunoprecipitation. The results indicated that LPS treatment decreased cell viability of primary chondrocytes, and increased apoptosis rate and production of IL-1β, IL-6 and TNF-α. The expression level of miR-200b was downregulated, and that of FUT4 was upregulated in OA cartilage tissues and LPS-treated normal chondrocytes compared with normal cartilage tissues and chondrocytes. Overexpression of miR-200b via transfection with miR-200b mimic inhibited the apoptosis rate and reduced the levels of IL-1β, IL-6 and TNF-α in LPS-stimulated chondrocytes. However, the suppressive effect of miR-200b overexpression on the LPS-induced inflammatory injury in chondrocytes was reversed by the restoration of FUT4 levels. Notably, FUT4 was indicated to be a downstream target of miR-200b and was negatively regulated by miR-200b. Taken together, the results of the current study indicated that miR-200b protected chondrocytes from LPS-induced inflammatory injury in vitro by targeting FUT4. These findings revealed the miR-200b/FUT4 axis as a potential candidate to target the degeneration of cartilages, thereby inhibiting the progression of OA.

The function of lncRNAs in the pathogenesis of osteoarthritis

Osteoarthritis (OA), one of the most common motor system disorders, is a degenerative disease involving progressive joint destruction caused by a variety of factors. At present, OA has become the fourth most common cause of disability in the world. However, the pathogenesis of OA is complex and has not yet been clarified. Long non-coding RNA (lncRNA) refers to a group of RNAs more than 200 nucleotides in length with limited protein-coding potential, which have a wide range of biological functions including regulating transcriptional patterns and protein activity, as well as binding to form endogenous small interference RNAs (siRNAs) and natural microRNA (miRNA) molecular sponges. In recent years, a large number of lncRNAs have been found to be differentially expressed in a variety of pathological processes of OA, including extracellular matrix (ECM) degradation, synovial inflammation, chondrocyte apoptosis, and angiogenesis. Obviously, lncRNAs play important roles in regulating gene expression, maintaining the phenotype of cartilage and synovial cells, and the stability of the intra-articular environment. This article reviews the results of the latest research into the role of lncRNAs in a variety of pathological processes of OA, in order to provide a new direction for the study of OA pathogenesis and a new target for prevention and treatment. Cite this article: Bone Joint Res 2021;10(2):122-133.

Circular RNA CSNK1G1 promotes the progression of osteoarthritis by targeting the miR‑4428/FUT2 axis

Osteoarthritis (OA) is a chronic disease that results in chronic arthralgia and functional disability of the affected joint. To date, there is no effective treatment available for this disease. Circular RNAs (circRNAs) are a type of intracellular stable RNA that can regulate the development and progression of OA. However, the function of circCSNK1G1 in OA has not yet been investigated. In the present study, it was found that circCSNK1G1 was upregulated in OA cartilage tissues. The upregulation of circCSNK1G1 was associated with extracellular matrix (ECM) degradation and chondrocyte apoptosis. Moreover, the expression of miR‑4428 was downregulated and that of fucosyltransferase 2 (FUT2) was upregulated in OA‑affected cartilage tissues. Dual‑luciferase reporter assay and RNA immunoprecipitation confirmed that miR‑4428 targeted FUT2 mRNA to inhibit FUT2 expression. circCSNK1G1 and FUT2 induced ECM degradation and chondrocyte apoptosis. The negative effects of circCSNK1G1 and FUT2 were reversed by miR‑4428. On the whole, the present study demonstrates that circCSNK1G1 promotes the development of OA by targeting the miR‑4428/FUT2 axis. Thus, the circCSNK1G1/miR‑4428/FUT2 axis may present a novel target for the treatment of OA in the clinical setting.

MicroRNA-520c-3p targeting of RelA/p65 suppresses atherosclerotic plaque formation

Atherosclerosis is a chronic inflammatory disease, and it's the leading cause of death worldwide. Dysregulation of microRNAs (miRNAs) has been found to be associated with atherosclerosis. miR-520c-3p has been implicated in several types of cancer. However, little is known about the role of miR-520c-3p in atherosclerosis. In this study, we found that miR-520c-3p agomir decreased atherosclerotic plaque size, collagen content, the quantity of PCNA-positive cell and RelA/p65 expression of vascular smooth muscle cells (VSMCs) in the aortic valve of apoE^-/- mice in vivo. The possible mechanisms of the protective effects of miR-520c-3p on atherosclerotic mice were then investigated in VSMCs. in vitro experiments showed that miR-520c-3p expressions were significantly reduced in human aortic vascular smooth muscle cell (HASMCs) treated with platelet-derived growth factor (PDGF-BB). miR-520c-3p mimics repress PDGF-BB-mediated the proliferation, migration and decrease in the percentage of cells in G2/M phase, which was associated with downregulation of RelA/p65. Mechanistically, miRNA pull-down, luciferase reporter and mRNA stability assays confirmed miR-520c-3p mimics was able to directly target 3'-UTR of RelA/p65 mRNA and decreased half-life of RelA/p65 mRNA in HASMCs. Overexpression of RelA/p65 reversed the inhibition of cell proliferation induced by miR-520c-3p mimics in HASMCs. In conclusion, our findings suggest that miR-520c-3p inhibits PDGF-BB-mediated the proliferation and migration of HASMCs by targeting RelA/p65, which may provide potential therapeutic strategies in atherosclerosis treatment.

Mesenchymal stem cell-derived exosomal microRNA-136-5p inhibits chondrocyte degeneration in traumatic osteoarthritis by targeting ELF3

BACKGROUND

Emerging evidence suggests that microRNAs (miRs) are associated with the progression of osteoarthritis (OA). In this study, the role of exosomal miR-136-5p derived from mesenchymal stem cells (MSCs) in OA progression is investigated and the potential therapeutic mechanism explored.

METHODS

Bone marrow mesenchymal stem cells (BMMSCs) and their exosomes were isolated from patients and identified. The endocytosis of chondrocytes and the effects of exosome miR-136-5p on cartilage degradation were observed and examined by immunofluorescence and cartilage staining. Then, the targeting relationship between miR-136-5p and E74-like factor 3 (ELF3) was analyzed by dual-luciferase report assay. Based on gain- or loss-of-function experiments, the effects of exosomes and exosomal miR-136-5p on chondrocyte migration were examined by EdU and Transwell assay. Finally, a mouse model of post-traumatic OA was developed to evaluate effects of miR-136-5p on chondrocyte degeneration in vivo.

RESULTS

In the clinical samples of traumatic OA cartilage tissues, we detected increased ELF3 expression, and reduced miR-136-5p expression was determined. The BMMSC-derived exosomes showed an enriched level of miR-136-5p, which could be internalized by chondrocytes. The migration of chondrocyte was promoted by miR-136-5p, while collagen II, aggrecan, and SOX9 expression was increased and MMP-13 expression was reduced. miR-136-5p was verified to target ELF3 and could downregulate its expression. Moreover, the expression of ELF3 was reduced in chondrocytes after internalization of exosomes. In the mouse model of post-traumatic OA, exosomal miR-136-5p was found to reduce the degeneration of cartilage extracellular matrix.

CONCLUSION

These data provide evidence that BMMSC-derived exosomal miR-136-5p could promote chondrocyte migration in vitro and inhibit cartilage degeneration in vivo, thereby inhibiting OA pathology, which highlighted the transfer of exosomal miR-136-5p as a promising therapeutic strategy for patients with OA.

CCAL1 enhances osteoarthritis through the NF-κB/AMPK signaling pathway

Osteoarthritis (OA) is a chronic joint disease characterized by articular cartilage degeneration and secondary osteogenesis. It has been previously demonstrated that the CCAL1 locus is the gene encoding tumor necrosis factor receptor superfamily member 11B (TNFRSF11B). The purpose of this study was to demonstrate the role of CCAL1 in OA progression and to elucidate its molecular mechanisms. We report that CCAL1 is highly expressed in the cartilage of OA patients and its expression level is positively correlated with the severity of OA. We found that CCAL1 causes a switch to the fibrosis‐prone phenotype of Human Chondrocyte‐Osteoarthritis (HC‐OA) cells. In addition, CCAL1 enhances cell viability and promotes the proliferation of HC‐OA cells. Finally, the detection of proteins associated with the NF‐κB/AMPK signaling pathway by western blot suggested that CCAL1 exerts its role on HC‐OA cells by activating the NF‐κB signaling pathway and inhibiting the AMPK signaling pathway, which was verified through the addition of NF‐κB inhibitor caffeic acid phenethyl ester (CAPE) and AMPK activator 5‐aminoimidazole‐4‐carboxamide riboside (AICAR). In summary, we report that CCAL1 may promote OA through the NF‐κB and AMPK signaling pathways.

TUG1 knockdown promoted viability and inhibited apoptosis and cartilage ECM degradation in chondrocytes via the miR-17-5p/FUT1 pathway in osteoarthritis

Osteoarthritis (OA) is a degenerative disease characterized by cartilage destruction. Previous research has demonstrated that long non-coding RNAs serve a role in OA progression. The current study aimed to determine the function and mechanism of taurine upregulated gene (TUG) 1 in OA. The results of reverse transcription quantitative PCR revealed that TUG1 was elevated in OA cartilage tissues and interleukin (IL)-1β-induced chondrocytes. Cell Counting kit-8 and flow cytometry analysis revealed that TUG1 knockdown promoted cell viability and inhibited cell apoptosis. Furthermore, matrix metalloprotein (MMP) 13, collagen II and aggrecan expression was determined by western blotting, of which the results demonstrated that TUG1 knockdown significantly decreased MMP13 expression and increased collagen II and aggrecan expression in IL-1β-stimulated chondrocytes, indicating that extracellular matrix (ECM) damage was inhibited. Additionally, using bioinformatics analysis, dual-luciferase reporter and RNA immunoprecipitation assays, TUG1 was revealed to upregulate fucosyltransferase (FUT) 1 by targeting miR-17-5p. Furthermore, miR-17-5p was downregulated and FUT1 upregulated in OA cartilage tissues and IL-1β-induced chondrocytes. TUG1 overexpression reversed the aforementioned effects on cell viability, cell apoptosis and ECM degradation mediated by miR-17-5p in IL-1β-activated chondrocytes. Additionally, the effects of FUT1 knockdown on cell viability, apoptosis and ECM degradation mediated by FUT1 knockdown were reversed by miR-17-5p inhibition. In conclusion, TUG1 knockdown inhibited OA progression by downregulating FUT1 via miR-17-5p.

Sweet Control: MicroRNA Regulation of the Glycome

Glycosylation is a sophisticated informational system that controls specific biological functions at the cellular and organismal level. Dysregulation of glycosylation may underlie some of the most complex and common diseases of the modern era. In the past 5 years, microRNAs have come to the forefront as a critical regulator of the glycome. Herein, we review the current literature on miRNA regulation of glycosylation and how this work may point to a new way to identify the biological importance of glycosylation enzymes.

The Therapeutic Potential and Role of miRNA, lncRNA, and circRNA in Osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a disease characterized by progressive degeneration, joint hyperplasia, narrowing of joint spaces, and extracellular matrix metabolism. Recent studies have shown that the pathogenesis of OA may be related to non-coding RNA, and its pathological mechanism may be an effective way to reduce OA.

OBJECTIVE

The purpose of this review was to investigate the recent progress of miRNA, long noncoding RNA (lncRNA) and circular RNA (circRNA) in gene therapy of OA, discussing the effects of this RNA on gene expression, inflammatory reaction, apoptosis and extracellular matrix in OA.

METHODS

The following electronic databases were searched, including PubMed, EMBASE, Web of Science, and the Cochrane Library, for published studies involving the miRNA, lncRNA, and circRNA in OA. The outcomes included the gene expression, inflammatory reaction, apoptosis, and extracellular matrix.

RESULTS AND DISCUSSION

With the development of technology, miRNA, lncRNA, and circRNA have been found in many diseases. More importantly, recent studies have found that RNA interacts with RNA-binding proteins to regulate gene transcription and protein translation, and is involved in various pathological processes of OA, thus becoming a potential therapy for OA.

CONCLUSION

In this paper, we briefly introduced the role of miRNA, lncRNA, and circRNA in the occurrence and development of OA and as a new target for gene therapy.

Circular RNA-9119 protects IL-1β-treated chondrocytes from apoptosis in an osteoarthritis cell model by intercepting the microRNA-26a/PTEN axis

AIMS

Osteoarthritis (OA) is a common degenerative joint disease characterized by cartilage degeneration and joint inflammation. As its pathogenesis remains unclear, there are no effective treatments established. Circular RNA (circRNA), microRNA (miRNA), and other noncoding RNAs participate in OA development; however, the effects and mechanisms of circRNA and miRNA in OA remain unknown.

MAIN METHODS

Cartilage miRNA was examined in patients with and without OA.

KEY FINDINGS

CircRNA-9119 and phosphatase and tensin homolog (PTEN) expression decreased in OA-affected cartilage and interleukin (IL)-1β-induced chondrocytes, and miR-26a expression significantly decreased in normal cells and tissues. CircRNA-9119 overexpression restored chondrocyte growth, whereas IL-1β treatment impaired chondrocyte growth. Annexin V-FITC & PI flow cytometry and Bcl-2/Bax ratio measurement indicated that the apoptosis of IL-1β-treated articular chondrocytes was decreased by circRNA-9119 upregulation. Bioinformatic prediction and the dual-luciferase reporter assay indicated that circRNA-9119 served as a miR-26a sponge and that miR-26a targeted the 3'-UTR of PTEN. Transfection of chondrocytes with a circRNA-9119-overexpressing vector revealed downregulation of miR-26a expression. Furthermore, circRNA-9119 overexpression induced PTEN expression. In addition, a miR-26a mimic induced IL-1β-induced chondrocyte apoptosis, and circRNA-9119 overexpression inhibited IL-1β-induced chondrocyte apoptosis.

SIGNIFICANCE

CircRNA-9119 is an important regulator of IL-1β-treated chondrocytes through the miR-26a/PTEN axis, possibly contributing to OA development.

Noncoding RNAs: New regulatory code in chondrocyte apoptosis and autophagy

Osteoarthritis (OA) is a bone and joint disease characterized by progressive cartilage degradation. In the face of global trends of population aging, OA is expected to become the fourth most common disabling disease by 2020. Nevertheless, the detailed pathogenesis of OA has not yet been elucidated. Noncoding RNAs (ncRNAs), including long noncoding RNAs, microRNAs, and circular RNAs, do not encode proteins but have recently emerged as important regulators of apoptosis and autophagy of chondrocytes, thereby highlighting a potential role in chondrocyte injury leading to OA onset and progression. We here review recent findings on these regulatory roles of ncRNAs to provide new directions for research on the pathogenesis of OA and offer new therapeutic targets for prevention and treatment. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

Long non-coding RNA PVT1, a molecular sponge of miR-26b, is involved in the progression of hyperglycemia-induced collagen degradation in human chondrocytes by targeting CTGF/TGF- signal ways

The current study was conducted to investigate the role of long non-coding RNA PVT1 in hyperglycemia-triggered human osteoarthritis (OA) chondrocytes. Cartilage from knee OA patients with and without diabetes, as well as normal cartilage, was obtained. Isolated human chondrocytes were treated with 30 nM of Glc with or without pioglitazone. The expression levels of PVT1, miR-26b, and type II collagen were determined by RT-PCR. Type II collagen was detected by immunocytochemistry and chondrocytes were stained with Alcian blue. Moreover, the interaction among PVT1, miR-26b, and CTGF was examined using bioinformatics, FISH, RIP, RNA-pull down, and luciferase reporter assays. Over-expression of PVT1 and miR-26b were performed and expressions of CTGF, TGF-β1, SMAD3, MMP-13, and type II collagen proteins were examined. Significantly higher expression of PVT1 was observed in diabetic OA. High Glc induced the elevated expression of PVT1, CTGF, TGF-β1, IL-6, and MMP-13, as well as decreased expression of type II collagen and miR-26b. These alterations could be reversed by pioglitazone. PVT1 acted as a sponge for miR-26b to facilitate CTGF expression. Over-expression of PVT1 increased the expressions of CTGF, TGF-β1, SMAD3, and MMP-13 and decreased expression of type II collagen. Our findings confirmed that PVT1 is involved in the hyperglycemia-induced collagen degradation, via the miR-26b-CTGF-TGF-β1-axis.

MicroRNA-26b inhibits oligodendrocyte precursor cell differentiation by targeting adrenomedullin in spinal cord injury

Oligodendrocyte precursor cells (OPCs) serve as a reservoir of newborn oligodendrocytes (OLs) in pathological and homeostatic conditions. After spinal cord injury (SCI), OPCs are activated to generate myelinating OLs, contributing to remyelination and functional recovery; however, the underlying molecular mechanisms remain unclear. Here, microRNA-26b (miR-26b) expression in the spinal cord tissues of SCI rats was examined by real-time polymerase chain reaction analysis. The influences of miR-26b on locomotor recovery following SCI were assessed utilizing Basso, Beattie, and Bresnahan (BBB) scores. The effects of miR-26b on OPC differentiation were explored using immunofluorescence and western blot analyses in vitro and in vivo. The potential targets that are modulated by miR-26b were identified by bioinformatics, luciferase reporter assays, and western blot analyses. The effects of adrenomedullin (ADM) on OPC differentiation were explored in vitro using immunofluorescence and western blot analyses. We demonstrated that miR-26b was significantly downregulated after SCI. BBB scores showed that miR-26b exacerbated the locomotor function deficits induced by SCI. In vitro, miR-26b inhibited the differentiation of primary rat OPCs. In vivo, miR-26b suppressed OPC differentiation in SCI rats. Bioinformatics analyses and experimental detection revealed that miR-26b directly targeted ADM in OPCs. In addition, knockdown of ADM suppressed the differentiation of primary rat OPCs. Our study provides evidence that ADM may mediate miR-26b-inhibited OPC differentiation in SCI.

Hyaluronic Acid: Molecular Mechanisms and Therapeutic Trajectory

Hyaluronic acid (also known as hyaluronan or hyaluronate) is naturally found in many tissues and fluids, but more abundantly in articular cartilage and synovial fluid (SF). Hyaluronic acid (HA) content varies widely in different joints and species. HA is a non-sulfated, naturally occurring non-protein glycosaminoglycan (GAG), with distinct physico-chemical properties, produced by synoviocytes, fibroblasts, and chondrocytes. HA has an important role in the biomechanics of normal SF, where it is partially responsible for lubrication and viscoelasticity of the SF. The concentration of HA and its molecular weight (MW) decline as osteoarthritis (OA) progresses with aging. For that reason, HA has been used for more than four decades in the treatment of OA in dogs, horses and humans. HA produces anti-arthritic effects via multiple mechanisms involving receptors, enzymes and other metabolic pathways. HA is also used in the treatment of ophthalmic, dermal, burns, wound repair, and other health conditions. The MW of HA appears to play a critical role in the formulation of the products used in the treatment of diseases. This review provides a mechanism-based rationale for the use of HA in some disease conditions with special reference to OA.

Interleukin-1 receptor antagonist protein (IL-1Ra) and miR-140 overexpression via pNNS-conjugated chitosan-mediated gene transfer enhances the repair of full-thickness cartilage defects in a rabbit model

Objectives

Previously, we reported the improved transfection efficiency of a plasmid DNA-chitosan (pDNA-CS) complex using a phosphorylatable nuclear localization signal-linked nucleic kinase substrate short peptide (pNNS) conjugated to chitosan (pNNS-CS). This study investigated the effects of pNNS-CS-mediated miR-140 and interleukin-1 receptor antagonist protein (IL-1Ra) gene transfection both in rabbit chondrocytes and a cartilage defect model.

Methods

The pBudCE4.1-miR-140, pBudCE4.1-IL-1Ra, and negative control pBudCE4.1 plasmids were constructed and combined with pNNS-CS to form pDNA/pNNS-CS complexes. These complexes were transfected into chondrocytes or injected into the knee joint cavity.

Results

High IL-1Ra and miR-140 expression levels were detected both in vitro and in vivo. In vitro, compared with the pBudCE4.1 group, the transgenic group presented with significantly increased chondrocyte proliferation and glycosaminoglycan (GAG) synthesis, as well as increased collagen type II alpha 1 chain (COL2A1), aggrecan (ACAN), and TIMP metallopeptidase inhibitor 1 (TIMP-1) levels. Nitric oxide (NO) synthesis was reduced, as were a disintegrin and metalloproteinase with thrombospondin type 1 motif 5 (ADAMTS-5) and matrix metalloproteinase (MMP)-13 levels. In vivo, the exogenous genes reduced the synovial fluid GAG and NO concentrations and the ADAMTS-5 and MMP-13 levels in cartilage. In contrast, COL2A1, ACAN, and TIMP-1 levels were increased, and the cartilage Mankin score was decreased in the transgenic group compared with the pBudCE4.1 group. Double gene combination produced greater efficacies than each single gene, both in vitro and in vivo.

Conclusion

This study suggests that pNNS-CS is a good candidate for treating cartilage defects via gene therapy, and that IL-1Ra in combination with miR-140 produces promising biological effects on cartilage defects.

Cite this article: R. Zhao, S. Wang, L. Jia, Q. Li, J. Qiao, X. Peng. Interleukin-1 receptor antagonist protein (IL-1Ra) and miR-140 overexpression via pNNS-conjugated chitosan-mediated gene transfer enhances the repair of full-thickness cartilage defects in a rabbit model. Bone Joint Res 2019;8:165–178. DOI: 10.1302/2046-3758.83.BJR-2018-0222.R1.

pNNS-Conjugated Chitosan Mediated IGF-1 and miR-140 Overexpression in Articular Chondrocytes Improves Cartilage Repair

The aim of the present study was to investigate the effects of phosphorylatable nucleus localization signal linked nucleic kinase substrate short peptide (^pNNS)-conjugated chitosan (^pNNS-CS) mediated miR-140 and IGF-1 in both rabbit chondrocytes and cartilage defects model. ^pNNS-CS was combined with pBudCE4.1-IGF-1, pBudCE4.1-miR-140, and negative control pBudCE4.1 to form pDNA/^pNNS-CS complexes. Then these complexes were transfected into chondrocytes or injected intra-articularly into the knee joints. High levels of IGF-1 and miR-140 expression were detected both in vitro and in vivo. Compared with pBudCE4.1 group, in vitro, the transgenic groups significantly promoted chondrocyte proliferation, increased glycosaminoglycan (GAG) synthesis, and ACAN, COL2A1, and TIMP-1 levels, and reduced the levels of nitric oxide (NO), MMP-13, and ADAMTS-5. In vivo, the exogenous genes enhanced COL2A1, ACAN, and TIMP-1 expression in cartilage and reduced cartilage Mankin score and the contents of NO, IL-1β, TNF-α, and GAG contents in synovial fluid of rabbits, MMP-13, ADAMTS-5, COL1A2, and COL10A1 levels in cartilage. Double gene combination showed better results than single gene. This study indicate that ^pNNS-CS is a better gene delivery vehicle in gene therapy for cartilage defects and that miR-140 combination IGF-1 transfection has better biologic effects on cartilage defects.

Redox and NF-κB signaling in osteoarthritis

Human cells have to deal with the constant production of reactive oxygen species (ROS). Although ROS overproduction might be harmful to cell biology, there are plenty of data showing that moderate levels of ROS control gene expression by maintaining redox signaling. Osteoarthritis (OA) is the most common joint disorder with a multi-factorial etiology including overproduction of ROS. ROS overproduction in OA modifies intracellular signaling, chondrocyte life cycle, metabolism of cartilage matrix and contributes to synovial inflammation and dysfunction of the subchondral bone. In arthritic tissues, the NF-κB signaling pathway can be activated by pro-inflammatory cytokines, mechanical stress, and extracellular matrix degradation products. This activation results in regulation of expression of many cytokines, inflammatory mediators, transcription factors, and several matrix-degrading enzymes. Overall, NF-κB signaling affects cartilage matrix remodeling, chondrocyte apoptosis, synovial inflammation, and has indirect stimulatory effects on downstream regulators of terminal chondrocyte differentiation. Interaction between redox signaling and NF-κB transcription factors seems to play a distinctive role in OA pathogenesis.

Onset and Progression of Human Osteoarthritis-Can Growth Factors, Inflammatory Cytokines, or Differential miRNA Expression Concomitantly Induce Proliferation, ECM Degradation, and Inflammation in Articular Cartilage?

Osteoarthritis (OA) is a degenerative whole joint disease, for which no preventative or therapeutic biological interventions are available. This is likely due to the fact that OA pathogenesis includes several signaling pathways, whose interactions remain unclear, especially at disease onset. Early OA is characterized by three key events: a rarely considered early phase of proliferation of cartilage-resident cells, in contrast to well-established increased synthesis, and degradation of extracellular matrix components and inflammation, associated with OA progression. We focused on the question, which of these key events are regulated by growth factors, inflammatory cytokines, and/or miRNA abundance. Collectively, we elucidated a specific sequence of the OA key events that are described best as a very early phase of proliferation of human articular cartilage (AC) cells and concomitant anabolic/catabolic effects that are accompanied by incipient pro-inflammatory effects. Many of the reviewed factors appeared able to induce one or two key events. Only one factor, fibroblast growth factor 2 (FGF2), is capable of concomitantly inducing all key events. Moreover, AC cell proliferation cannot be induced and, in fact, is suppressed by inflammatory signaling, suggesting that inflammatory signaling cannot be the sole inductor of all early OA key events, especially at disease onset.

Long non-coding RNA HOTAIR promotes osteoarthritis progression via miR-17-5p/FUT2/β-catenin axis

Osteoarthritis (OA) is a chronic joint disease and hard to cure at present. Accumulating evidence suggests long noncoding RNA-HOTAIR (lncRNA-HOTAIR) plays important role in OA progression. However, the underlying molecular mechanism of HOTAIR in OA progression has not been well elucidated. In the present study, we identified that HOTAIR level was upregulated in OA cartilage tissues. High expression of HOTAIR was correlated with modified Mankin scale, extracellular matrix (ECM) degradation and chondrocytes apoptosis. The expression of miR-17-5p was down-regulated, while alpha-1, 2 fucosyltransferase 2 (FUT2) was increased in OA progression. Luciferase reporter and RNA immunoprecipitation (RIP) assays indicated that HOTAIR could directly bind to miR-17-5p and indirectly upregulate FUT2 level. Functional investigation revealed HOTAIR and FUT2 aggravated ECM degradation and chondrocytes apoptosis, and this effect could be reversed by miR-17-5p. Altered FUT2 modulated the activity of wnt/β-catenin pathway and HOTAIR/miR-17-5p also mediated wnt/β-catenin pathway through FUT2. Collectively, our findings indicated that HOTAIR/miR-17-5p/FUT2 axis contributed to OA progression via wnt/β-catenin pathway, which might provide novel insights into the function of lncRNA-driven in OA.

miR-140-5p/miR-149 Affects Chondrocyte Proliferation, Apoptosis, and Autophagy by Targeting FUT1 in Osteoarthritis

Osteoarthritis (OA), the most prevalent chronic and degenerative joint disease, is characterized by articular cartilage degradation and chondrocyte injury. Increased cell apoptosis and defective cell autophagy in chondrocytes are a feature of degenerative cartilage. MicroRNAs (miRNAs) have been identified as potential regulators of OA. This study aimed to determine the potential role of miR-140-5p and miR-149 in apoptosis, autophagy, and proliferation in human primary chondrocytes and investigate the underlying mechanism. We revealed the differential expressional profiles of miR-140-5p/149 and fucosyltransferase 1 (FUT1) in the articular cartilage tissues of OA patients and normal people and validated FUT1 was a direct target of miR-140-5p/149. The overexpression of miR-140-5p/149 inhibited apoptosis and promoted proliferation and autophagy of human primary chondrocytes via downregulating FUT1. On the contrary, the downregulation of miR-140-5p/149 inhibited chondrocyte proliferation and autophagy, whereas the effect was reversed by FUT1 knockdown. Taken together, our data suggested that miR-140-5p and miR-149 could mediate the development of OA, which was regulated by FUT1. miR-140-5p/miR-149/FUT1 axis might serve as a predictive biomarker and a potential therapeutic target in OA treatment.